Golang实现RFC 3315标准DHCPv6服务器功能插件库dhcp6的使用

dhcp6是一个实现了RFC 3315标准DHCPv6服务器的Go语言库，采用MIT许可证授权。

功能概述

该库目前提供了DHCPv6服务器的基本实现，未来计划还将实现客户端和测试工具。需要注意的是，当前API尚未稳定，可能会随时间变化。

安装

使用go get命令安装：

go get github.com/mdlayher/dhcp6

基本使用示例

下面是一个简单的DHCPv6服务器实现示例：

package main

import (
	"log"
	"net"
	
	"github.com/mdlayher/dhcp6"
	"github.com/mdlayher/dhcp6/dhcp6opts"
)

func main() {
	// 创建UDP连接，监听DHCPv6服务器端口(547)
	conn, err := dhcp6.NewServerConn()
	if err != nil {
		log.Fatalf("无法创建服务器连接: %v", err)
	}
	defer conn.Close()

	// 定义IP地址池
	ipPool := []net.IP{
		net.ParseIP("2001:db8::1"),
		net.ParseIP("2001:db8::2"),
		net.ParseIP("2001:db8::3"),
	}
	
	// 定义其他配置选项
	dnsServers := []net.IP{
		net.ParseIP("2001:4860:4860::8888"), // Google DNS
		net.ParseIP("2001:4860:4860::8844"), // Google DNS
	}
	
	// 处理DHCPv6请求
	for {
		// 接收请求
		packet, addr, err := conn.ReadFrom()
		if err != nil {
			log.Printf("读取数据包错误: %v", err)
			continue
		}
		
		// 只处理Solicit请求
		if packet.MessageType != dhcp6.MessageTypeSolicit {
			continue
		}
		
		// 从请求中获取客户端DUID
		clientID, err := dhcp6opts.GetClientID(packet.Options)
		if err != nil {
			log.Printf("获取客户端ID错误: %v", err)
			continue
		}
		
		// 分配IP地址
		// 这里简化处理，实际应用中应该有更复杂的分配逻辑
		assignedIP := ipPool[0]
		
		// 构建响应选项
		opts := make(dhcp6.Options)
		opts.Add(dhcp6.OptionClientID, clientID)
		opts.Add(dhcp6.OptionServerID, []byte{0x00, 0x01, 0x00, 0x01, 0x0a, 0x0a, 0x0a, 0x0a})
		opts.Add(dhcp6.OptionDNSRecursiveNameServer, dhcp6opts.IPs(dnsServers).ToBytes())
		
		// 创建Advertise响应
		resp := &dhcp6.Packet{
			MessageType:   dhcp6.MessageTypeAdvertise,
			TransactionID: packet.TransactionID,
			Options:       opts,
		}
		
		// 发送响应
		if _, err := conn.WriteTo(resp, addr); err != nil {
			log.Printf("发送响应错误: %v", err)
		}
		
		log.Printf("已为客户端 %x 分配IP %s", clientID, assignedIP)
	}
}

高级示例：完整DHCPv6服务器实现

下面是一个更完整的DHCPv6服务器实现，处理多种消息类型：

package main

import (
	"log"
	"net"
	"time"
	
	"github.com/mdlayher/dhcp6"
	"github.com/mdlayher/dhcp6/dhcp6opts"
)

type DHCPv6Server struct {
	conn      *dhcp6.Conn
	ipPool    []net.IP
	leases    map[string]net.IP
	dns       []net.IP
	serverID  []byte
}

func NewServer() (*DHCPv6Server, error) {
	conn, err := dhcp6.NewServerConn()
	if err != nil {
		return nil, err
	}
	
	return &DHCPv6Server{
		conn:     conn,
		ipPool:   []net.IP{
			net.ParseIP("2001:db8::1"),
			net.ParseIP("2001:db8::2"),
			net.ParseIP("2001:db8::3"),
		},
		leases:   make(map[string]net.IP),
		dns: []net.IP{
			net.ParseIP("2001:4860:4860::8888"),
			net.ParseIP("2001:4860:4860::8844"),
		},
		serverID: []byte{0x00, 0x01, 0x00, 0x01, 0x0a, 0x0a, 0x0a, 0x0a},
	}, nil
}

func (s *DHCPv6Server) Run() {
	defer s.conn.Close()
	
	for {
		packet, addr, err := s.conn.ReadFrom()
		if err != nil {
			log.Printf("读取错误: %v", err)
			continue
		}
		
		go s.handlePacket(packet, addr)
	}
}

func (s *DHCPv6Server) handlePacket(packet *dhcp6.Packet, addr net.Addr) {
	clientID, err := dhcp6opts.GetClientID(packet.Options)
	if err != nil {
		log.Printf("无效客户端ID: %v", err)
		return
	}
	
	clientIDStr := string(clientID)
	
	switch packet.MessageType {
	case dhcp6.MessageTypeSolicit:
		s.handleSolicit(packet, addr, clientIDStr)
	case dhcp6.MessageTypeRequest:
		s.handleRequest(packet, addr, clientIDStr)
	case dhcp6.MessageTypeRenew:
		s.handleRenew(packet, addr, clientIDStr)
	case dhcp6.MessageTypeRelease:
		s.handleRelease(packet, addr, clientIDStr)
	default:
		log.Printf("未知消息类型: %v", packet.MessageType)
	}
}

func (s *DHCPv6Server) handleSolicit(packet *dhcp6.Packet, addr net.Addr, clientID string) {
	// 检查是否已有租约
	ip, exists := s.leases[clientID]
	if !exists {
		// 分配新IP
		if len(s.ipPool) == 0 {
			log.Printf("IP地址池已耗尽")
			return
		}
		ip = s.ipPool[0]
		s.ipPool = s.ipPool[1:]
		s.leases[clientID] = ip
	}
	
	// 构建Advertise响应
	opts := s.buildOptions(clientID)
	resp := &dhcp6.Packet{
		MessageType:   dhcp6.MessageTypeAdvertise,
		TransactionID: packet.TransactionID,
		Options:       opts,
	}
	
	if _, err := s.conn.WriteTo(resp, addr); err != nil {
		log.Printf("发送Advertise失败: %v", err)
	}
}

func (s *DHCPv6Server) handleRequest(packet *dhcp6.Packet, addr net.Addr, clientID string) {
	// 确认租约
	_, exists := s.leases[clientID]
	if !exists {
		log.Printf("客户端 %s 无有效租约", clientID)
		return
	}
	
	// 构建Reply响应
	opts := s.buildOptions(clientID)
	opts.Add(dhcp6.OptionIAAddress, dhcp6opts.IAAddress{
		IP:        s.leases[clientID],
		Preferred: 2 * time.Hour,
		Valid:     4 * time.Hour,
	}.ToBytes())
	
	resp := &dhcp6.Packet{
		MessageType:   dhcp6.MessageTypeReply,
		TransactionID: packet.TransactionID,
		Options:       opts,
	}
	
	if _, err := s.conn.WriteTo(resp, addr); err != nil {
		log.Printf("发送Reply失败: %v", err)
	}
}

func (s *DHCPv6Server) buildOptions(clientID string) dhcp6.Options {
	opts := make(dhcp6.Options)
	opts.Add(dhcp6.OptionClientID, []byte(clientID))
	opts.Add(dhcp6.OptionServerID, s.serverID)
	opts.Add(dhcp6.OptionDNSRecursiveNameServer, dhcp6opts.IPs(s.dns).ToBytes())
	return opts
}

func (s *DHCPv6Server) handleRenew(packet *dhcp6.Packet, addr net.Addr, clientID string) {
	// 更新租约时间
	if _, exists := s.leases[clientID]; exists {
		s.handleRequest(packet, addr, clientID)
	}
}

func (s *DHCPv6Server) handleRelease(packet *dhcp6.Packet, addr net.Addr, clientID string) {
	// 释放IP地址
	if ip, exists := s.leases[clientID]; exists {
		delete(s.leases, clientID)
		s.ipPool = append(s.ipPool, ip)
		log.Printf("已释放客户端 %s 的IP %s", clientID, ip)
	}
}

func main() {
	server, err := NewServer()
	if err != nil {
		log.Fatalf("创建服务器失败: %v", err)
	}
	
	log.Println("DHCPv6服务器启动...")
	server.Run()
}

注意事项

1. 该库API尚未稳定，可能会发生变化
2. 实际生产环境中需要考虑更复杂的IP地址管理、租约持久化等特性
3. 需要正确处理各种DHCPv6消息类型和选项
4. 需要考虑网络安全性和性能优化

以上示例展示了如何使用dhcp6库实现基本的DHCPv6服务器功能，包括处理Solicit、Request、Renew和Release等消息类型。开发者可以根据实际需求扩展这些基础功能。